Method of hydrogenating coumarone-indene resin



Patented Mar. 4, 1947 I METHOD OF HYDROGENATING COUMA- BONE-INDENE RESINWilliam H. Carniody, deceased, late of Springfield, Ohio, by Marie 0.Carmody, administrairlx, Springfield, Ohio, asslgnor to Carmody ResearchLaboratories, Inc., Springfield, Ohio, a

corporation of Ohio No Drawing. Application December 3, 1943, Serial No.512.787

Claiml- (Cl. 260-81) This invention relates to the selectivehydrogenation of indene and coumarone polymers. The application hereinis a continuation-in-part of the application of William H. Carmody,Serial No. 280,128, filed June 20, 1939. I

In the production of coumarone-lndene resins by the polymerization ofthe resin-forming unsaturates coumarone and indene which occur in thecrude solvent naphtha from coke oven light oil, in the coal-derived dripoils, and in the recycle oils from cyclization processes, thereresultant polymers, representing all the different orders ofpolymerization, possess unsaturation of two sorts. One sort ofunsaturation is in the benzene rings of the monomeric units which arelinked to form the polymer, and the other sort of unsaturation occurssolely in the terminal unit of each of the polymers. In indene polymersunsaturation of the latter sort is in the cyclopenta diene structure ofthe final monomeric unit of the polymer. It is the premise, supported byexperience, that the yellowing of coumarone and indene substances occursby reaction at the terminal double bond or point of unsaturation of eachof the polymers. This phenomenon of "yellowing is a seriouslydisadvantageous property of the resins composed of the polymers ofindene and of coumarone, and of mixtures of those polymers. Forconvenience it is considered the chemical mechanism by which yellowingoccurs in coumarone and indene polymers to be a fulvenation reaction inwhich there initially is a combination with oxygen accelerated bysubjection to ultra-violet rays as in sunlight.

It has been the experience of the art that the initial purity of acoumarone-indene resin, by which is meant a resin composed of thepolymers of indene or composed of the polymers of coumarone as well as aresin composed of mixtures of those polymers, takes place in spite ofthe greatest care which may be exercised to obtain a resin whichinitially is of high purity. Whereas the yellowing reaction which istermed fulvenation tends to occur during the progress of thecondensation and polymerization reaction by which the polymers areformed to produce initially discolored or highly coloredcoumarone-indene resins, it occurs progressively in resins which by careexercised in their formation are initially of very light olor. Taking acoumarone-indene resin whicl has been carefully prepared for maximumpurity and which is initially thus of very light yellow coloration in amass or lump,

such resin is capable of producing a film which as initially depositedfrom solution is apparently colorless. This initially colorless fllmupon exposure to light and air will, however, rapidly and progressivelydarken until it has acquired a reddish brown or dark brown coloration.

It is the premise that this yellowing of coumarone and indene polymersoccurs by aldehyde development in the terminal unit of the coumarone andindene polymers. Each such terminal unit, like the other units of thepolymeric structure, has three double bonds in the benzene ring of theunit. Unlike the other units of the polymeric structure, however, it hasan initial nonnuclear double bond lying outside the benzene ring oraromatic nucleus of the structure. Thus it we assume the formula for theindene monomet to be as iollows:

Formula A H0 at Since the addition product is relatively, unstable,

this residual acid radical splits off to regenerate the double bond inthe structure which it vacates. The same mechanism will occur in thecase of trimers, tetramers and higher polymers comprising any givennumber of monomeric units, the double bond in the structure outside thearomatic nucleus in the terminal unit of the polymer being regeneratedas a final incident to the polymerization. This leaves the terminalindene the following condition:

Formula 8 H t R n-o C(IJ g at t a...

in which "R represents the remainder of the polymeric structurecomprising any given number of indene units. Similarly, the terminalunit 01' the coumarone polymer may be considered as having the followingstructure:

Formula C unit in in which likewise "R represents the remainingmolecular structure of the polymer comprising any given number ofcoumarone units.

It may be taken as a fact that the polymerization of indene and ofeoumarone proceeds identically, although the tendency of the indene isto build up to polymers higher than those of the coumarone, that is topolymers comprising a greater number of monomeric units. Resins composedof a mixture of coumarone and indene polymers will, therefore, be takenherein as 'to mechanism of polymerization and discoloration, as alsoillustrative of resins formed of unmixed polymers of either coumarone orindene.

It is this double bond outside the aromatic nucleus in the terminal unitof the polymer which is susceptible to oxidation, and it is a hydrogenatom adjacent this double bond which reacts to form acids, aldehydes andketones. Both hydrogen atoms adjacent the double bond in question (inthe monomer) are easily replaced by organic radicals, complexes orresidues either successively or simultaneously.

Since it will be understood that fulvenation, or discoloration, can berepresented in terms of oxygen addition at this non-nuclear double bondor the terminal unit, it has been discovered that by blocking thepossibility of oxygen combining with the terminal indene unit, the colordevelopment which is termed fulvenation can be precluded. Theoreticallythis can be accomplished in any manner which efiects a saturation of thedouble bond which is outside of the aromatic nucleus, this double bondbeing designated A in the simplified formulae given above. Saturation atthis point blocks the en line of reaction step by which discolorati nproceeds, and the polymer saturate at such point indefinitely willretain its initial color.

Experience has shown that hydrogenation so conducted as to saturatesubstantially all the polymers of a polymerized body of indene at thispoint in the terminal units of the polymers, while giving a resinousbody protected against discoloration does not greatly increase thesolubility of such body. Also as an observation coniirmatory of thepremise as to the point of attack in an indene polymer to producediscoloration, it has been observed that the lower indene polymers, suchas the indene dimers, discolor more rapidly than do the higher indenepolymers and ultimately attain a deeper coloration. Whereas, saturationwith hydrogen at the point "A" in the terminal unit of the indenepolymers results in producing polymers which are protected againstdiscoloration, but the solubility of which is not substantiallyincreased, a general attack 4 upon the polymers by means of hydrogen hasa different eiifect. Thus if indene polymers be indiscriminatelyhydrogenated with saturation o! a substantial proportion of the doublebond in the aromatic nuclei of the polymers, the solubility of thepolymers may be greatly increased by a quantitatively great introductionof hydrogen, but to the extent that the specified nonnuclear doublebonds of the polymers have not been saturated by contact with hydrogen,the polymers retain their capacity for the.yellowing" reactions.

In the hydrogenation of coumarone-indene resin and other resins metalcatalysts such as Raney nickel catalyst has been largely employed. Raneynickel is an extremely active hydrogenation catalyst for the polymers ofcoumaroneindene resin in all orders of polymerization, and its actionrenders the progress of hydrogenation extremely difllcult to controlwhen that catalyst is used. Even though it be desired to saturate withhydrogen only the non-nuclear double bond outside the benzine ring oraromatic nucleus in the terminal unit of the several polymers of theresin, the activity of the catalyst causes hydrogen in some measurepromiscuously also to enter the double bonds throughout the polymers.Thus the hydrogenation of coumarone-indene polymers with Raney nickelcatalyst tends to produce a resin which is of increased solubility, andalso to produce a coumarone-indene resin which is of improved colorstability by saturation of some 01. the non-nuclear double bonds outsidethe aromatic nuclei. In accordance with the above discussion. saturationof the double bonds in the aromatic nuclei has no effect in preventingcolor development in the polymers of the resin. This is true of allthecoumarone-indene polymers from the dimers to those polymers containing agreat number of the indene or coumarone units. In order, therefore, toobtain a coumarone-indene resin of good color stability by hydrogenationwith Raney nickel catalyst it is necessary to hydrogenate under suchconditions as to efiect substantially complete hydrogenation of theseveral polymers of the resin throughout their chemical structure.Otherwise there is marked lack of color stability in the hydrogenatedresins.

The present invention oflers a full and satisfactory answer to theproblem of producing nonyellowing or color-stable coumarone-indeneresin, by a method economical in its consumption of hydrogen andmoderate in its hydrogenating conditions. Recognizing that for somepurposes it may be and is desired to introduce hydrogen partially orfully to saturate the double bonds in the aromatic nuclei of the resinpolymers such is not within the compass of my present invention, nor

does the accomplishment of that result of itself impart chemicalstability and color stability to the resin.

It will readily be appreciated wherein the econ.- omy of thishydrogenation method resides in the light of the fact that theprevention of yellowing can be fully accomplished by hydrogensaturatingthe two carbon atoms adjacent the non-nuclear double bond in theterminal unit of the resin polymers. As the size of the polymeric resinmolecule increases, 1. e., as the number of proportionately less withrespect to the molecular weight of the molecule. Thg with liquidcoumarone-indene resins composed of coumarone and indene dimers andother low-melting coumaroneindene resins containing a relatively largeproportion of dimers or other of the lower polymers, the'quantity ofhydrogen required for color stabilizing hydrogenation is much greaterproportionately than with a resin composed wholly or chiefly of polymersformed of a relatively great number of monomeric units. Whereas theeconomy of this method in consumption of hydrogen is, therefore, moststriking in the higher molecular weight and higher meltingcoumarone-indene resins, it is also economical in the case of allpolymers down to and including the coumarone and indene dimers.Regardless of the polymer size the effect in color-stabilization ispositive.

In conducting the method of this invention hydrogenation is performed inthe presence of black copper oxide as a selective hydrogenationcatalyst. Black copper oxide is not as energetic in its catalytic effectas metallic nickel and the important difference in its action is that itdoes not attack promiscuously all the double bonds of the resin moleculeincluding those in the aromatic nucleus or benzene ring, but isselective in its action causing attack by hydrogen only at theabove-mentioned non-nuclear terminal double bond with entry of twomolecules of hydrogen into the polymeric resin molecule at that point.

This may be proved by subjecting benzene to a hydrogenation treatmentwith black copper oxide catalyst. There was placed 100 cc. of anapproximately pure benzene fraction, consisting in substantial entiretyof simple monomeric benzene ring structures, in a hydrogenation bombwith 6 grams of black copper oxide. The bomb was closed and hydrogen wasrun in under pressure. The maximum temperature was 100 C. and theinitial pressure 1000 pounds per square inch. The final pressure was1000 pounds per square inch, showing that no hydrogen was introducedinto the benzene rings or absorbed by the catalyst. The addition ofmonomeric indene to benzene and similar aromatic solvent substancespresenting no point of unsaturation exterior to the benzene ringresulted, under identical hydrogenating conditions, in a consumption ofhydrogen very close to that theoretically required to saturate the twocarbon atoms which give the single point of unsaturation in thenon-nuclear structure of the indene.

Experiment has shown that the quantity of black copper oxide catalystpreferably should be about 5% to 15% the weight of the resin. Althoughthis roportion is approximately that used in the case of Raney nickelcatalyst, the black copper oxide presents a distinct advantage becauseof its lower cost compared with Raney nickel, because of the fact thatit is less susceptible to catalyst poison, and because no specialprecautions are required in connection with its preparation, storage, oruse. These advantages are aside from the advantage of black copper oxidecatalyst in producing a definitely non-yellowauaoos 6 substantially theminimum quantity of catalyst with which the desired results will, besecured:

and although a percentage of the catalyst greater gen. Experiment hasshown that 5 grams of black ,copper oxide catalyst to each 100 grams ofresin is the results may be comparative in their illustration. In theprocedure of all the following examples a standard hydrogenation bombwas used; the resin was ground; and the ground resin together withsolvent and catalyst was placed in the bomb and the bomb thenclosed.Hydrogen gas was admitted to the bomb from a suitable supply, as fromcylinders of compressed hydrogen at the pressure desired for eachparticular experiment. The whole assembly was then placed in rotatingmechanism of suitable well-known kind and was warmed by gas burners. Thebomb is fitted with a thermometer well carrying a thermometer in theusual manner.

During the progress of the hydrogenation the rotating mechanism wasstopped at intervals to observe data as to time, pressure andtemperature. When the reaction was completed as indicated by cessationin pressure drop within the bomb, the temperature was restored to itsinitial value and the pressure was again observed. The bomb was venteddownto atmospheric pressure and its contents were removed. The catalystwas removed from the reaction solution by filtration and the solvent wasremoved by steam distillation. These procedures yield a molten residualresin, which is poured into a pan to harden.

Except in those instances in which some element of the reaction mixturewas omitted for the purpose of checking the essential features or inwhich certain observations were considered unnecessary, the foregoingprocedure was in every instance followed. Also in operating to obtainrecordable data, the usual precautions were taken to ensure that theexperiments were as quantitative as possible and each bomb, therefore,was carefully calibrated to volume and the volume of the reactionmixture deducted from it. The figure so secured represented the hydrogengas volume in the bomb, from which calculations gave the number of cubiccentimeters of hydrogen gas employed. This volume wascompared with theexpected or theoretical value based on the weight of the resin subjectedto treatment, and the approximate average molecular weight of thepolymers hydrogenated.

1 The invention herein may be exemplified as folows:

Example 1 grams of coumarone-indene resin, having a melting point of C.(cube in mercury), together with 100 cc. of petroleum benzine and 10grams of black copper oxide catalyst, was placed in a bomb having avolume of 920 cc. The volume of charge was 200 cc., thus leaving a spacehaving a volume of 720 cc. for the hydrogen gas. The bomb was sealed andhydrogen was run in with heating of the bomb and rotation in the mannerabove described.

The time of treatment was 3 hours. The maximum operating temperature was159v C. The initial pressure was 1290 lbs. per square inch, agree}! thefinal pressure was 1224 lbs. per square This run shows a pressure dropof 66 pounds over the course of the reaction. 66 pounds divided by 14.7(1 atmosphere of pressure) equals 4.48. This multiplied by 720 gives3220 cc. of hydrogen consumed by the 100 grams of resin. 100 grams ofthe resin is 0.13 mol. of resin and requires 2890 cc. of hydrogen tosaturate the single non-nuclear double bond of each resin molecule, andrequires 57,800 cc. of hydrogen to completely saturate the rings, or atotal of 60,690 cc. to totally saturate all the points in "the resin.The selectivity of the hydrogenation catalyst used is noted by com aring3220 cc. actually used with 2890 cc. required for the one non-nucleardouble bond.

The average molecular weight of this coumarone-indene resin meltingclose to 150 C. (cube in mercury) is approximately 775. number of unitsin the resin molecules averages about 6.67. Two atoms of hydrogen areneeded to saturate two non-nuclear unsaturate carbon atoms of eachpolymer, and there are three double bonds in the benzene ring of eachunit of the polymer. Remembering that the average number of units in thepolymer is 6.67 for this particular resin, itwill require 3n 1 mol. ofhydrogen wholly to saturate each resin molecule. In this instance itbeing 6.67, a total of 21 mols. is required wholly to saturate thehenzene rings or aromatic nuclei of the average resin molecule. as wellas the non-nuclear terminal of the molecule. The ratio of hydrogenrequired to eliminate the non-nuclear double bond to that requiredwholly to saturate the molecule is 1 to 21, which is 4.75% of themaximum potential hydrogen consumption, and 4.7% of 60,690 cc. is about2890 cc. In Example 1 the hydrogen consumption of 3220 cc. shows thatthe single terminal non-nuclear double bond of each resin molecule issaturated 5.27%, which means that there has been some slightintroduction of hydrogen into the aromatic nuclei of the coumarone andindene units comprised in the polymeric resin molecules, but that suchnuclear saturation is not substantial.

In order for Raney nickel to have done as well in saturating thenon-nuclear double bond it would have to saturate also the benzene ringsof the resin molecules, and as above explained, such saturation isunnecessary in obtaining a non-yellowing coumarone-indene resin.

The resin produced in Example 1 was a clear, colorless resin. Whenexposed to ultra-violet light in a weathermeter for 48 hours, it showedno trace of yellowing. After exposure to sunlight for a period of threemonths another sample of the resin showed barely perceptiblediscoloration.

It is to be understood that in the ratio represented by l to 311. 1, nis a variable which represents the average number of units in thepolymeric molecules of any coumarone-indene resin under consideration.

Inasmuch as the coumarone and indene polymers each present the severaldiverse points of attack by hydrogen which have been above discussed,the total proportional volume of hydrogen absorbed by any given weightof the resin is not conclusive as to the selectivity of thehydrogenation. The following example is, however, conclusive in showingthe selectivity of hydrogenation in the presence of black copper oxidecatalyst.

Example 2 63 grams oi app roximately pure indene and The- 8 51 grams ofhigh-flash solvent. naphtha, were placed in the bomb with 6 grams ofblack copper oxide catalyst. .The anticipated consumption of hydrogenfully to hydrogenate the nonnuclear bonds throughout the entire body ofthe indene was 11,760 cc. Hydrogenation was conducted at an operatingtemperature close to 100 C. at an initial pressure 01' 1435 lbs. and ata final pressure of 1220 lbs. The observed hydrogen consumption was11,700 cc. It will be noted that in the above both the indene and anarcmatic solvent were present. Had Raney nickel catalyst been used, theresult would have been a total hydrogenation of both components and thevolume of hydrogen gas absorbed would have been very much greater than11,700 cc. With black copper oxide catalyst it wasto be ticipated thatonly the indene monomer wou d be acted upon and that the aromaticsolvent would be unattacked, and also that only the non-nuclear doublebond of the indene monomer would be hydrogenated. On this basis it wascomputed that 11,700 cc. proves the selective effect of the catalystwithin reasonable experimental error. a

It is an important advantage of black copper oxide, as a hydrogenationcatalyst for coumaroneindene resin such as with the chromitehydrogenation catalysts useoi which is exemplified in detail incompanion application Serial No. 512,785, filed December 3, 1943, thatby its use non-yellowing ccumarone-indene resins can be produced byhydrogenation attemperatures far below those commonly employed in thecatalytic hydrogenation of resins. Whereas it has been usual in the pastto efiect such reaction at temperatures of about 200 C. and much higher,black copper oxide catalyst gives good results at temperatures withinthe approximate range of 100 C. to 175 C., and even at temperatures aslow as C. or C. The following example describes a hydrogenationtreatment purposely conducted at low temperature to determinewhattemperature, if any, represents the critical minimum in producing a.non-yellowing resin from coumaroneindene resin by hydrogenation.

Example 3 grams of coumarone-indene resin having a melting point of C.(cube in mercury) was placed in the hydrogenation bomb with 100 cc. ofthe aliphatic hydrocarbon solvent Varnolene and 10 grams of black copperoxide catalyst. Hydrogen was run in. Because of the low temperaturerange employed in this exemplary hydrogenation treatment, a pressurehigher than that of Example 1 was used. The initial hydrogen pressure.was 1835 lbs. per square inch, and the initial temperature was 19 C. Thetime of treatment was about 2% hours. The temperature was raisedprogressively during the treatment and apparently no substantialhydrogenation occurred until the temperature rose to about 50 C. As thetemperature was increased from 50 C. to 76 C. there was an increase inpressure from 2000 lbs. per square inch to 2170 lbs. per square inch.Such apparent increase in pressure was, however, due to risingtemperature, and there was in fact a substantial hydrogen absorption.When the batch was cooled to the original temperature of 19 C., thepressure dropped to 1780, showing an actual pressure loss of 55 lbs.This 55 lb. decrease in pressure corresponds to 2950 cc. of hydrogen, ora percentage of 4.86% the total volume of hydrogen the coumarone-indeneresin is capable of taking. Analysis shows that the reaction wassubstantially complete at about 70 C. to C.

The coumarone-indene resin subjected to this hydrogenation treatment wastested for its retention of the yellowing tendency and was found to havealmost as good color stability as those resins which were treated athigher temperatures.

As to the factors of temperature and pressure, it is apparent from theforegoing discussion and exempliflcation that relatively low temperatureand relatively low pressure is adequate to effect hydrogenation ofcoumarone-indene resin with black copper oxide catalyst in a molecularratio of approximately 1:1. Somewhat higher temperatures may be used,desirably by hydrogenating initially at a temperature below 200 C. andraising the temperature of the reaction mixture at a point where theabsorption of hydrogen tends to lag. By so doing the time required for athorough saturation at the non-nuclear double bonds in the resinmolecules may be shortened. In no case, however, do I find it desirableto utilize a maximum temperature in excess of 225 C. when using blackcopper oxide as a catalyst. In no case do I find it desirable to conductthe hydrogenation under a pressure substantially in excess of 2100 lbs.per square inch.

The following two examples illustrate hydrogenation with black copperoxide catalyst under what may be considered average and usualtemperature and pressure conditions for this hydrogenation process.

Example 4 100 grams of the same coumarone-indene resin and 100 cc. ofthe aliphatic hydrocarbon solvent Varnolene were placed in the bomb withgrams of black copper oxide catalyst and hydrogen was run in underpressure. The operating temperature of the reaction was about 141 C. Theinitial pressure was 1850 lbs. and the final pressure was 1795 lbs.

The actual consumption of hydrogen was 2948 00., which gives a ratio of4.85% to the total volume of hydrogen which would have been absorbed hadall the double bonds of all the molecules been saturated.

Example 5 100 grams of the same coumarone-indene resin and 100 cc. ofpetroleum benzine were placed in the bomb with 10 grams of black copperoxide catalyst and hydrogen was run in under pressure.

The operating temperature of the reaction was close to 157 C. Theinitial pressure was 1010 lbs. and the final pressure was 950 lbs.

The actual consumption of hydrogen was 2940 cc., which gives a ratio of4.84% to the total volume of hydrogen which would have been absorbed hadall the double bonds of all the molecules been saturated.

In connection with hydrogenation carried out in accordance with thepresent invention, it has been discovered that a number of difierentsolvents can be used satisfactorily, such as methylcyclohexane,ethyl-acetate, petroleum benzine, diethyl ether, and dibutyl phthalate,and that in general solvents can be satisfactorily employed which fallwithin any one of the following five classifications:

l. Cycloparaffins 2. Aliphatic esters 3. Straight chain paraflins 4.Ethers 5. Aromatic acid esters 10 The following five experimentsindicate results secured by the use of black copper oxide oncoumarone-indene resin with some of those solvents. from which it willbe understood that the solvent does not interfere with hydrogenation nordoes it particularly influence it.

Example 6 100 grams of coumarone-indene resin having a melting point 01'150 C. (cube in mercury) and 100 cc. of methyl-cyclohexane were placedin the bomb with 10 grams .of black copper oxide catalyst and hydrogenwas run in under pressure. The operating temperature of the reaction wasclose to 162 .C. The initial pressure was 1015 lbs. and the finalpressure was 960 lbs.

The actual consumption of hydrogen was 2950 cc., which gives a ratio of4.86% to the total volume of hydrogen which would have been absorbed hadall the double bonds of all the molecules been saturated.

Example 7 Example 8 grams of the same coumarone-indene resin and 100 cc.of diethyl ether were placed in the bomb with 10 grams of black copperoxide catalyst and hydrogen was run in under pressure. The initialpressure was 1000 lbs. and the iinal pressure was 925 lbs.

The actual consumption of hydrogen was 3680 cc., which gives a ratio of5.9% to the total volume of hydrogen which would have been absorbed hadall the double bonds of all the molecules been saturated.

Example 9 100 grams of the same coumarone-indene resin and 100 cc. ofdibutyl phthalate were placed in the bomb with 10 grams of black copperoxide catalyst and hydrogen was run in under pressure. The operatingtemperature of the reaction was close to 156 C. The initial pressure was1000 lbs. and the final pressure was 935 lbs.

The actual consumption of hydrogen was 3180 cc., which gives a ratio of5.2% to the total volume of hydrogen which would have been absorbed hadall the double bonds of all the molecules been saturated.

Example 10 In order to check the molecular efiect of the hydrogenationmethod, a liquid oily coumaroneindene resin was taken melting below 0 C.and composed chiefly of the dimers of coumarone and indene. 100 grams ofthis low-melting coumarone-indene resin was placed in the bomb with 10grams of black copper oxide catalyst, without solvent, and hydrogen wasrun in under pressure. The operating temperature was close to 225 C. Theinitial pressure was 1100 lbs. and the final pressure was 910 lbs.

hydrogen required to saturate the lone terminal I double bond of eachmolecule is approximately 14% of that required fully to hydrogenate themolecule and the consumption of 11,500 cc. of hydrogen represents 118%of that required to eliminate the non-nuclear double bonds, or 14.8% ofthe total hydrogen consumption required wholly to saturate the moleculesof the resin.

In the case of this liquid coumarone-indene resin, consistingapproximately 100% of coumarone-indene dimers, the average number ofunits in the molecules is two, so that the formula 1:3n+1 gives a ratioof 1:7. or approximately 14%, in comparing saturation of the terminalnon-nuclear structure with saturation of the entire molecular structure.

It is to be understood of all the foregoing examplesthat the treatedresin was substantially colorless. When exposed to ultra-violet light ina "weathermeter for 48 hours it showed no trace of yellowing." Afterexposure to sunlight for a period of three month other samples of theresins were justperceptibiy "yellowed.

Remembering always that the purpose of this invention is to saturateonly the one specific double bond of the resin polymers in as high anorder of completeness as may be possible, it will be seen that this hasbeen eflected in simple manner and by moderate operating conditions.Thus with the relatively high melting coumarone-indene resin chieflyexemplified above, the average structure of the resin polymers as tomonomeric units included in them is such that a quantity of hydrogenfairly close to 5% of that required for theoretically completesaturation of all the units of all the molecules is required for mypurpose. The absorption of a substantially greater proportion ofhydrogen would indicate absorption into the double bonds comprised inthe benzene rings of the several monomeric units of the molecules, andvalues below about 3% of the theoretically complete saturation wouldindicate that a large proportion of the resin molecules remainunsaturated as to the one nonnuclear double bond of each. The results ofall the examples are to be considered as satisfactory in effectingapproximately complete saturation at the non-nuclear double bonds of thepolymers without substantially saturating at the double bonds in thearomatic nuclei or benzene rings of the polymers.

The above discussion and examples deal with and exemplify the use ofhydrogenation in the presence of black copper oxide as the sole catalystused, and demonstrate the satisfactory effect of hydrogenation in thepresence of that catalyst. It is to be understood, however, that thehydrogenation may be conducted in the simultaneous presence of blackcopper oxide and one of the chromite catalysts, the use of which isdisclosed and exemplified in companion application Serial No. 512,785,filed December 3, 1943. That is, the black copper oxide may be used invaried proportions with one or more of copper chromite, iron chromiteand nickel chromite. When so used the diversity in the combined catalystappears to give a catalyst-promoting effect, so that a given quantity ofthe combined catalyst is somewhat more eflective than the same quantityof either catalyst alone. That is, the mixture or simultaneous use ofblack copper oxide and one or more catalysts from the group consistingof copper chromite, iron chromite and nic e chromite appears to indicatethat in the presence of the other both the black copper oxide and thechromite catalyst are slightly more effective than either when used byitself. Insofar as quantity of such mixture, either made in advance orin the bomb, is concerned, it is desirable to follow the catalystproportions given above for black copper oxide when used alone. That is,it is desirable to use a weight 0! combined catalyst equal to from 5% to15% the I weight of the coumarone-indene resin which'is subject tohydrogenation.

It is to be understood that in the foregoing where melting point isgiven without qualification, it is to be taken as. determined by thecube in mercury method of melting point determination. As explained. theterm "coumaroneindene resins" is to be taken as inclusive of resinscomposed of the polymers of either of those two substances, as well asresins composed of a mixture of polymers of the two. Where pressure isgiven in pounds without other explanation, it is to be taken as meaningpounds per square inch. Where parts or proportions are given withoutexpress or implied qualification as to comparison of volumes, it is tobe taken that parts by weight is intended. Where a monomeric substance,or resin, is named as indene in discussion or illustration above,"coumarone is to be understood as alternatively applicable, the twobeing interchangeable in the terms of the speci flcation.

What is claimed is:

1. A method of selectively hydrogenating coumarone-indene resin whichcomprises the steps of bringing such coumarone-indene resin into contactwith hydrogen in the presence of black copper oxide at a temperatureranging from about 75 C. to 225 C. and under a pressure not exceeding2100 pounds per square inch, thereby to chemically saturate only thenon-aromatic double bond which characterizes the indene and coumaroneresin structure. a

2. A method of selectively hydrogenating coumarone-indene resin whichcomprises the steps of bringing such coumarone-indene resin into contactwith hydrogen in the presence of black copper oxide at a temperatureranging from about 75 C. to 225 C. and under a pressure not exceeding2100 pounds per square inch, thereby to chemically saturate only thenon-aromatic double bond which characterizes the indene and coumaroneresin structure, the conditions being controlled to limit thecombination of resin and hydrogen to a molecular ratio of 1:1.

3. A method of selectively hydrogenating coumarone-indene resin whichcomprises the steps of bringing such coumarone-indene resin into contactwith hydrogen in the presence of black copper oxide under suchtemperature and pressure conditions as chemically to saturate only thenon-aromatic double bond which characterizes the indene and coumaroneresin structureythe selective hydrogenation being carried out at atemperature ranging from about 75 C. to 225 C. and at an initialpressure ranging from about 1000 pounds per square inch to 1850 poundsper temperature ranging from about 75 C. to 225 C.

being effected step-wise by controlling the temperature in such mannerthat it does not exceed 200 C. in the first stage thereof with thebalance of the selective hydrogenation being carried out at thetemperature of approximately 225 C. and at a pressure not exceeding 2100pounds per square inch.

5. A method of selectively hydrogenating coumarone-indene resin whichcomprises the steps of bringing such coumarone-indene resin into contactwith hydrogen in the presence of black copper oxide at a temperatureranging from about 75 C. to 225 C. and under a pressure not exceeding2100 pounds per square inch, thereby to chemically saturate only thenon-aromatic double bond which characterizes the'indene and coumaroneresin structure, the said coumaroneindene resin being in dissolved formand the catalyst constituting about 5% to 15% by weight of the saidresin.

MARIE 0. CARMODY.

Administratrix of the Estate of William H. Ca 25 4979 (1939)- mody,Deceased.

nmaancas cm? file of this patent:

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